1. Field of the Invention
This invention relates to electrical connectors, and in particular to components having arrays of elastic contacts.
2. Background of the Invention
As the need for device performance enhancement in electronic components drives packaging technology to shrink the spacing (or “pitch”) between electrical connections (also referred to as “leads”), a need exists to shrink the size of individual connector elements. In particular, packaging that involves advanced interconnect systems, such as interposers, can have large arrays of contacts, where individual electrical contacts in the array of contacts are designed to elastically engage individual electrical contacts located in a separate external device, such as a PCB board, IC chip, or other electrical component.
Although interposers, IC chips, PCB boards and other components are typically fabricated in a substantially planar configuration, often the contacts within a given component do not lie within a common plane. For example, an interposer with contacts arranged in substantially the same plane may be coupled to a PCB that has contacts at various locations on the PCB that have varying height (vertical) with respect to a horizontal plane of the PCB. In order to accommodate the height variation, the interposer contacts can be fabricated with elastic portions that are deformable in a vertical direction over a range of distances that accounts for the anticipated height variation.
As device size shrinks and the amount of components per unit area on electrical components increases, the pitch of contact arrays in interconnect systems such as interposers must be reduced. As used herein, the terms “pitch” or “array pitch” refer to the center-to-center distance of nearest neighbor contacts in an array of contacts, where the distance is typically measured in a direction within a horizontal plane of the contact array. Concomitant with reduction of array pitch is a reduction in average size of the contacts within the array (also termed “array contacts”). This results in a reduction in the dimensions of elastic portions of the contacts, which are typically configured as arms or beams that extend from a base contact in a three dimensional manner above a surface defined by the contact base. This reduction in contact arm length in turn leads to an undesirable reduction in the height variation through which the contact arm can be displaced, and therefore a reduction in height variation of an external component that can be accommodated by the interposer contact array.